With all of the instrument upgrades, the original single 12 volt 12 amp battery would not last long.
I was told I would need to get two 12 volt 9/10 amp batteries to replace the single one.
So, I did!
Now the problem is, the two batteries don't fit in the original battery box in the fuselage, oh, if there were placed up-right, they would, but they now sit in such a way, that the battery contacts are not accessible.
The width of the two batteries together were just a little wider than the box. (photo of the original box with the new batteries after the box was cut out).
The battery box placement is critical.
The main gear strut, when retracted, rest against the box.
The width was the only part of the box that needed to be modified.
The outline shown here is a bit of an exaggeration, but you see, the new design would not prevent the gear from retracting fully.
The first step was to create a mold for the batteries. I used wood to create a block the shape of the new battery box insides.
The mold gave me a few problems with the release due to using paint as a sealant, and not pre-planning a knock-out plug near a side on the bottom.
After the first couple of layers of glass were applied and cured, I tried to remove the shell.
Even though I applied a release agent, the shell had to be cut on the sides to be removed from the mold because of the poor design of the pattern.
I added several layer of glass over the outside of the box until I achieved the same thickness as the original.
I then created a shelf around the lip of the box and reinforced it with a fillet of glass roving to match the original
The old box was cut out using a variety of tools. It was tricky due to the confined space.
Here is a shot of the new box next to the original one.
After widening out the opening, and cleaning up the edges, I began to test fit the box in place.
I removed the excess shelf lip to match the fit of the original.
The next trick is to use a hot glue gun to tack a few spots to hold the box in place before applying the fiberglass patchwork.
I used some resin thickened with cotton flock to fill in the areas the were opened along the edge line.
After that had cured, I began adding the fiberglass strips to bond the box into place.
I added several layer to the outside of the box within the wheel well, and along the sides.
I covered the wet glass with peel ply to prevent the glass from lifting and shifting while the resin was curing.
After the resin cured, the peel ply was removed and any rough edges were sanded off.
After the final sanding was completed, I brushed on a thin layer of resin to seal open pores in the glass to prevent any moisture or contamination attacking the glass from inside the wheel well.
Now that the new box was installed, it was time to test fit the batteries while in the plane.
Due to the confined space, I found it difficult to remove the batteries. There was no real way to get a hold of them.
I devised a lift cradle for one battery using a plastic file folder cut and folded to the shape of the battery.
I added some nifty handles, which were made of plastic coated wire for strength.
Only one needed to be made. One one battery was out, getting the second one out was easy.
And here is the finished product!
The next step to complete this part of the project, is the battery box cover to prevent them from jumping out.
That is still in the works!
Do I smell more resin in the future?!
"Lay on, Macduff,
And damn'd be him that first cries, 'Hold, enough!'"
And damn'd be him that first cries, 'Hold, enough!'"
